June 12, 2004

The search for life in space, these days on Mars, is a result of a major paradigm shift that occurred with the discovery in the late seventies of ocean vents and the ecosystems that thrive around them. In 1977, as the submersible Alvin sank 8000 feet on a routine study of the ocean floor, unbelieving human eyes stared at what appeared to be a scene out of science fiction. Tube worms which are normally as big as a hand, grew 8ft tall at a depth of 2km down in the ocean. Indeed, there was a whole ecosystem thriving on the black coloured water that was spewing out of chimneys from the ocean floor at temperatures exceeding 360°C.

Having seeped through cracks in the ocean floor the water had gotten super heated by coming into contact with magma, the molten rock beneath the surface of the earth. Dissolving minerals into it as it searched for a way out, the expanded superheated water burst out of chimneys on the ocean floor. At this depth it was pitch black as absolutely no light of the sun penetrates this deep. The pressure of the water was equivalent to half the Empire State building made of solid lead pressing down on one. And the poisonous soup of chemicals dissolved in the super-heated water coming out of the vents on the ocean bottom were hitherto considered lethal to life as we knew it.

“Paradigm changes can result from discovery brought about by encounters with anomaly” explains Professor Frank Pajares in a synopsis of Thomas S. Kuhn’s ‘The Structure of Scientific Revolutions.’ And what the people in Alvin saw that day was, indeed, very strange, hardly believable. What was particularly shocking about the discovery was that this ecosystem existed independent of the energy derived from our sun.

As late as 1977 it had been assumed that all life on earth was ultimately dependent on sunlight. At the beginning of each food chain were plants that converted light energy from the sun into chemical energy, by the process of photosynthesis. Plants were then ingested by animals, including humans, who depend for their energy requirements on consuming organic matter, such as plants or other animals. So the paradigm that science worked off of was that all life on earth was dependent on the energy from sunlight that plants trapped into their bodies. In other words, without sunlight eventually all living creatures on earth would starve and die.

It turns out that there are thermophilic bacteria that use the hydrogen sulphide from the mineral rich water spewing out of the vents as an energy source and use it to make food out of the carbon dioxide and oxygen also in the environment. What these bacteria do with hydrogen sulphide is analogous to what plants do with photic energy. They oxidize hydrogen sulphide and the energy released from the process is used to power the conversion of carbon dioxide into organic molecules — food.

The tubeworms survive without mouth or anus by harbouring billions of these bacteria inside them. The blood of the tubeworm brings all the raw ingredients to the bacteria, which in turn leak the food they make by chemosynthesis (as opposed to photosynthesis), into the tubeworm’s body. Shrimp, numbering in the millions, and crabs nibble on the tubeworms for food.

More than 300 new species have been discovered in this ecosystem around ocean vents, the survival of all of which depend on the unique abilities of these heat-loving bacteria. Mussels, clams, miniature lobsters, worms, octopuses and all sorts of creatures are to be found around hydrothermal vents. These creatures are similar to but not the same as the ones found elsewhere in the ocean. For instance, the shrimp found here don’t have eyes. Gigantism, as seen with the tubeworms, also happens to be an unusual feature of many of the creatures that live in the deep ocean. At least several hundred such communities around hydrothermal vents in the ocean floor are now known to exist.

Since our discovery of these ocean vent communities, our view of life has changed. We had thought all life was powered by the Sun. But it turns out that there are creatures who need not the sun but in the case of hydrothermal vent bacteria, hydrogen sulphide, to survive.

In addition, scientific endeavour has resulted in the discovery of bacteria living within mussels that require methane as their inorganic energy supply. Thomas Gould at Cornell University first formally speculated that with life existing under such extreme and “hostile” conditions on earth, long ecosystems powered by other than the sun, why could life not similarly exist on other planets or their moons in our solar system. This thinking is now part of “normal science” and Nasa states its first “broad, overarching goal” for Mars exploration as being to “determine if life ever arose on Mars.”

Given that less than 1 per cent of the ocean floor has been explored by humans, God knows what other surprises await us at these depths. While the Rover explores the surface of Mars similar expeditions down to the ocean floor might surprise us with creatures we hitherto considered the stuff of myths and legends.

Our “scientific” vision of under what circumstances life was possible was limited by what we had seen and is again currently limited by what we have seen since. But the human mind if it takes help from the Creator of all nature can make faster and more precise progress. Einstein, for instance, said that “the greatest mistake of his career” was to put aside his calculations in theoretical physics which indicated that the universe was not static. Nobel prizes were subsequently awarded to scientists as more and more evidence piled up for the Big Bang theory.

The Big Bang theory states that the universe has not been eternally existent, that it had a point and time of origin and that it has been expanding ever since. Einstein laid his discovery to rest so as not to conflict with the paradigm prevalent in the early twentieth century which found the idea of a non-static universe repugnant. One who believed the Quran might not have put Einstein’s calculations aside as too incredulous for having read the words, “It is We who have built the universe…and it is We who are steadily expanding it” which clearly contradict the steady-state model of the universe. As can be seen, the problem with human-made paradigms is that we set ourselves up to be constrained by the limitations of the human mind.

The under-water world around hydrothermal vents in the ocean floor had probably been around for millennia, obscure from our vision, unknown to our imagination, defying what the human mind thought possible.

It is time we took a step back, re-examined our place in creation, and humbly submitted ourselves to the intelligence and capability responsible for the Big Bang. We are immune to the miracles we witness everyday, it takes a bit of a surprise to shake off some of our nonchalance about the way the world runs. Amazing though the human mind is; able to make machines that sample this life at the bottom of the ocean and that take off into space and send us pictures of the moons of Jupiter. These machines only try to see what is already made and what continues to run century after century according to the programme written out for it. As the bough laden with fruit bows low, so too the human mind most aware is humblest.

The writer is a molecular biologist from Yale University, Connecticut, USA. She writes independently on issues of contemporary interest

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